Apparatus for destroying banknotes

Abstract

In a high-speed sorter, single documents such as banknotes are successively withdrawn from a stack and tested according to various criteria. Banknotes which are authentic but no longer fit for circulation are fed to a cutting means a shredder and destroyed therein. The shredder, which has a simple construction and is designed for a high banknote throughput, consists of two cutter blocks including overlapping cutter discs which work into one another with little play in spaced relationship and are provided along their periphery with notches, and which slit and crosscut the banknotes. A suction plant prevents back-ups from forming, cleans and cools the cutting means.

We claim: 
     
       1. An apparatus for high speed shredding documents such as banknotes in a high-speed sorter, in which sorter the documents are removed from a stack one by one, tested according to various criteria and assigned to certain sorting classes as a result of the testing, one sorting class embracing documents which are supplied by a conveyor system to a shredder means and destroyed therein, comprising a shredder means including overlapped cutter disks mounted in fixed, spaced apart relationship on parallel rotatable shafts so that the disks are spaced apart from each other, each cutter disk including peripheral crosscutting notches that are out of registration with notches of adjacent disks; a collecting means for the document shreds disposed downstream of the shredder in the direction of movement of the documents; and a vacuum pump arranged to produce low pressure in the collecting means;   said collecting means including an entry opening, through which opening air is sucked through the shredder means due to the low pressure in the collecting means; and wherein said shredder means includes air conducting means forming flow channels through and around said cutter disks, said flow channels increasing the velocity of air sucked through the channels such that banknote shreds sticking to the cutter disks are stripped off and that the cutter disks are exposed to a flow of cooling air through and around the cutter disks.   
     
     
       2. An apparatus for high speed shredding documents such as banknotes in a high-speed sorter, in which sorter the documents are removed from a stack one by one, tested according to various criteria and assigned to certain sorting classes as a result of the testing, one sorting class embracing documents which are supplied by a conveyor system to a shredder means and destroyed therein, comprising a shredder means including overlapped cutter disks mounted in fixed, spaced apart relationship on parallel rotatable shafts so that the disks are spaced apart from each other, each cutter disk including peripheral crosscutting notches that are out of registration with notches of adjacent disks; a collecting means for the document shreds disposed downstream of the shredder means in the direction of movement of the documents; and a vacuum pump arranged to produce low pressure in the collecting means;   said collecting means including an entry opening, through which opening air is sucked through the shredder means due to the low pressure in the collecting means;   said entry opening being configured and oriented relative to said shredder means in such a way that most of said air follows the same path as the banknotes approaching the shredder means from the conveyor system; and wherein said shredder means includes air conduction means forming flow channels through and around said cutter disks, said flow channels increasing the velocity of air sucked through the channels such that banknote shreds sticking to the cutter disks are stripped off and that the cutter disks are exposed to a flow of cooling air through and around thecutter disks.   
     
     
       3. The apparatus as claimed in claim 2 including air gaps at least between said entry opening and said shredder means, whereby due to the low pressure, ambient air is also sucked through said air gaps. 
     
     
       4. An apparatus for high speed shredding documents such as banknotes in a high-speed sorter, in which sorter the documents are removed from a stack one by one, tested according to various criteria and assigned to certain sorting classes as a result of the testing, one sorting class embracing documents which are supplied by a conveyor system to a shredder means and destroyed therein, comprising a shredder means including overlapped cutter disks mounted in fixed, spaced apart relationship on parallel rotatable shafts so that the disks are spaced apart from each other, each cutter disk including peripheral crosscutting notches that are out of registration with notches of adjacent disks; a collecting means for the document shreds disposed downstream of the shredder means in the direction of movement of the documents; and a vacuum pump arranged to produce low pressure in the collecting means;   said collecting means including an entry opening, through which opening air is sucked through the shredder means due to the low pressure in the collecting means;   said low pressure being such, that the velocity of flow of the air is greater in the area of the shredder means that the speed of the documents approaching the shredder means from the conveyor system; and wherein said shredder means includes air conducting means forming flow channels through and around said cutter disks, said flow channels increasing the velocity of air sucked through the channels such that banknote shreds sticking to the cutter disks are exposed to a flow of cooling air through and around the cutter disks.